“Cloud cuckoo land” — A castle in the air. A fanciful state of unrealistic and over-optimistic thinking.
The term was brought into being with Aristophanes’s drama, The Birds, first performed in 414 BC. In this production, an Athenian named Pisthetaerus persuades the world’s birds to create a new city in the sky to be named “Nubicuculia” (Cloud Cuckoo Land). In this way, he hoped to gain control over communication between all men and gods.
An example of a “cloud cuckoo land” is Cockaigne (or Cockayne): a land of plenty in medieval myth. It is an imaginary place of extreme luxury and ease where physical comforts and pleasures are always immediately at hand and where the harshness of medieval peasant life does not exist.
Cockaigne is a land of “contraries,” where all the restrictions of society are defied (abbots beaten by their monks), sexual liberty is open (nuns flipped over to show their bottoms), and food is plentiful (skies that rained cheeses).